Television transmission



Feb. e, 1940c F. SCHRTER 2,189,351

TELEVISION TRANSMISSION Filed June 14, 1934' INVENTOR ATTRNEY greaterPatented Feb. 6, 1940 UNITED lsinrrss PATENT OFFICE funken Gesellschaftfr Drahtlose Telegraphie m. b. H., Berlin, Germany, a corporation of'Germany Application June 14, 1934, Serial No. 730,593

In Germany July 29, 1933 6 Claims.

The invention relates to the synchronous electrical distancetransmission of the picture and tone portion of normal talking films.

It has for its purpose, despite the necessary retaining of the filmvelocity established by the sound record reproduction, which today byestablished practice is normally 24 frame widths per second, which maybe illustrated by Way of eX- ample, to make possible a higher number ofpictures for the optical part of the transmission. It has been foundthat in the recently attained brilliancies of the picture screen, inparticular by the use of the Braun or cathode ray tube (the kinescope)as television picture producer, that the alternation of 24 pictures persecond frequently ceases to act sufficiently free of flickering, andthat a yquiet facial impression can only be attained at a somewhathigher alternation frequency.

In accordance therewith the present invention resides in the use andcombination of methods and arrangements which in the normal, for thetone recording properly adjusted advance of the film, permitsl of thescanning of a great many more pictures at the same time than pictureframes of normal dimension are mechanically released. In the followingit is assumed, for purposes of example and illustration only, that therequired number of optical transmissions per second, herein designatedby n, is equal to 36. The invention, however, permits of any other valuefor n and any desired proportion of this n to the acousticallyestablished value, designated as n', which today=24.

Fig. l shows the relative position of the scanning beams and frames of acontinuously moving iilm at different time intervals.

Fig. 2 shows diagrammatically an apparatus for performing the invention.

For the solutionof the present problem an optical picture compensationmethod is vinserted for the television scanning, and which at keepingconstant 1L=normal=24, permits an independent n, n' for the frequency ofthe light electrical decomposition and recomposition of the picturemosaic. An embodiment of the invention coml prises making a specialphotographic copy from the talking film to be transmitted, having in thelength of 1V=24 normal widths of pictures a number of picturescorrespondingly smaller in accordance with the assumption 11:36. Thereduction can be limited to the coordinate parallel to the advance ofthe nlm. This transformation of the respective section of thecinematographic act from 24 tov 36 individual phases or frames can beaccomplished in various Ways. One way resides in interconnecting anoptical picture balancer between "the original standard nlm and the copyto be made therefrom. In reproducing in this way the uniformly advancedoriginalnegative, or a positive` made therefrom, by means of a Mechauprojector (as illustrated, for example, by U. S. Patent 1,584,317granted to E. Mechau on May 11, 1926) or an equivalent device withproper reduction, on the step-like advanced copying strip, for exampleby means of a Maltese cross, and in selecting 36 steps for 24 standardpicture frames ofk lm length advanced, due to the continuous excessshutting of the individual picture phases there will be obtained on thecopy the desiredincreased number of discrete, sharp pictures of reducedsize, and hence 'a film is obtained directly suited for the standardtelevision scanning and which may have the sound record copied atftheedge thereof.

In another waythe photographic transmission can be carried lout on anauxiliary strip at a rational proportion-nm' for instance also 36/24, bymeans of special copying machines. These devices operate by the use ofrhythmically controlled, and operated shutters in such manner that at acorresponding reduction of vthe size Vof the picture at least of thewidth 'of the picture in the proportion 36/24, for each 2 pictureframesor phases of the original, three picture frames or phases of the copyare produced, in that, for' instance, each 1, 3, 5, etc., individualpicture of the original is twice copied in succession, while each 2nd,4th, 6th, etc., will be copied only once. Hence for 24 advanced frameWidths of the original 12 times 2 plus 12 times 1,) 36 reduced picturesare obtained in the copy. It is obvious that already at the originalproduction of the respective talking nlm, besides the ordinary apparatusa second apparatus can be synchronously operated therewith which asaforementioned receives for a length lof n standard widths of thepicture, directly n, n pictures.

v Besides the photographic compensation on film band proper theinvention can also be put into practice in such manner that the pictureseries of the standard talking lm band is projected on the scanningfield of the television decomposer in an optical way by means of a con-CFI the special case, projected on a Nipkow disk having spiral circlesof holes, and which operates in the known manner. Hence due to thesuperposition of the individual pictures on the disk withoutinterruption or gaps, a forced ratio of reduction between the disk andthe transport movement of the iilm is not required; the Nipkow disk onthe contrary may be driven, entirely independent, with that number ofrevolutions corresponding with the desired increased n of the opticalscanning.

A third possibility for carrying out the invention is obtained by theuse of the so-called Braun or cathode ray tube as picture scanner. Thisapplication has been proposed already in various instances. It consistsin moving the point of light on the fluorescent screen of the tube inthe sense of the decomposition of the picture whereby it can be sharplyprojected through a lens on to the iilm to be transmitted. Aphotoelectric cell disposed in back thereof receives in accordance withthe distribution of the black portions in the picture of the lm agreater or smaller amount of light. Since a continuous advance of thepicture band automatically furnishes the cross component of thetelevision decomposition in this arrangement the point of light can belimited to its movement within always the same trace of lines. This typeof scanning, as is known, can be accomplished in the cathode ray tube bymeans of relaxation oscillation deviating the electron beam at constantvelocity along the picture line in order to cause it to suddently returnto the starting point at the end of the line.

In order to carry out the invention by means of such cathode rayscanner, in addition to the before described operating performance, anelectrically cr magnetically effected periodical lateral displacement ofthe course of the picture points is carried out at right angle to theline. This displacement is transmitted to the picture film by means ofthe projector lens. The resultant rhythmic movement of the cross line isagainst the movement of the film operating at standard speed, untilunder the influence of the second relaxation oscillation by which it iscontrolled, it suddently jumps back into the starting point. Then itbegins anew.

This type of performance is schematically shown in Figure l of thedrawing wherein there is indicated eight diierent phases I-VIII of thedisplacement of the nlm band shown in cross seotion, whose individuallengths of the pictures is shown by the section l, 2, 3, etc. The lmmoves in a continuous fashion and not in sudden steps, in the directionof the arrows 3. Against this film there moves the location of thescanning line in the sense of arrow Il; however the same jumps back overan entire width of the picture within regular time intervalscorresponding with the phases II, V, VIII (arrow 9). While the lm in theexample chosen (nzi, 1L=24) advances at 2,5 of its standard width of thepicture, the scanning movement of the cross line of the point oflight'moves towards the film at 1/3 of the width of the picture. Afteran advance of the nlm of 2 times 2,@:9 normal picture widths, the courseof thev point of light hence has continuously passed over and scanned inlines 3 full pictures, as seen from Figure l. If therefore the band ofthe talking film is moved at a standard speed u'=24 picture Widths persecond, the light point decomposes in this line 24 times iQ-:36pictures. The dotted line represents the displacement as to time of thescanning line, and hence also the shape of the voltage of the relaxationoscillation necessary for the cathode ray deviation. In the intervals 11', `I'-", 7"-1" the snapping back of the cathode ray, i. e., therelaxation of the voltage at the important pair of deviation plates,takes place.

An example of one suitable arrangement for carrying out this control isshown in Figure 2. The film I is continuously moved and thereon the line2 of the light point of the cathode ray tube of which only the endsurfaces of the bulb I3 is indicated, is correspondingly reduced andsharply reproduced by means of the lens l. The incident light is passedto the photoelectric cell 9 by means of lens 8. The plate pair servingfor the line deviation of the light point is not shown in the drawing.At 90 displace thereto, there is provided a second plate pair 3, for therequired cross displacement in the sense of the invention, cf thescanning line 2 on the screen of tube I3, or on the nlm I respectively.This plate pair 3 is in parallel to the condenser' 4, which can beperiodically charged by a. direct voltage source across a resistance E.The entire arrangement conforms with an ordinary relaxation circuit, andhence all means known in such arrangements for obtaining a definitelyshaped charging current curve, can be applied, for instance, in place ofan ehmic resistance ti, an electron tube operating in the region ofsaturation, or better a pentode can be used whose anode current remainsconstant within a wide interval of the plate potential. For thedischarge of the condenser 4 or the plate pair 3 respectively, acontrolled discharge tube I2 serves, for instance, a glow relay orthyratron, whose grid is positively charged by a periodically operatedswitch II which is controlled by the movement of the nlm. To this endthe film is passed over rollers Iii, with which the switching device IIis coupled in a forced manner in the proper ratio oi reduction. In thismanner the cross movement of the line of the cathode ray, shown inFigure l, can be easily and simply controlled practically withoutenergy, and thus the desired compensation of the picture can be0btained.

The relaxation oscillation required for the compensation of the picturesand produced according to the method in Figure 2, may be used at thesame time for the synchronization of the cross deviation of the electronbeam in the picture receiver. Hereby it is necessary to transformupwards the relaxation frequency in the proportion 1h, since accordingto Figure 1 there corresponds with the interval between the individualrelaxation performances, the threefold transmission of the pictureiield. This frequency ratio is not required to be carried out in thereceiver, it can be produced already in the transmitter by means knownas such.

The invention is, of course, capable of modication and I, therefore,believe myself to bc entitled to make and use any and all modificationsthereof which fall fairly within the spirit and scope of the hereinafterappended claims.

What I claim and desire to protect by Letters Patent is:

l. In television apparatus, a. motion picture lm of which theelectro-optical image reproduction of each lm frame area is to beproduced at a distance point, means for moving the lm at apreestablished constant speed past a point of analysis, a. cathode raytube having means therein to produce a point source of light ofelemental area, an optical system to direct the light produced Withinthe cathode ray tube upon the nlm to illuminate an area of proportionalsize on the nlm, and a light translating device for producing whenilluminated in accordance with the varying densities of the nlm recordas illuminated by the cathode ray spot varying electrical energy outputcorresponding to the nlm density at the elemental area instantaneouslyilluminated, denecting means associated with the cat-hode ray tube forcausing the cathode ray beam developed to scan thenlm transversely in aline for line manner during the nlm motion past the predetermined pointvand a second denecting means for causingthe line for line scanning ofthe nlm frame areas passing before the predetermined point to be of adifferent number than the lines of elemental Width oi' the nlm actuallypassing the said predetermined point Within the said predetermined timeperiod.

2. In television apparatus, a `motion picture nlm record of which theelectro-optical image reproduction of the successive nlm frame areasthereof is to be produced, means for continuously moving the nlm past apredetermined point at` a pre-established constant rate corresponding tothe rate of nlm motion suitable for the translation of the sound recordaccompanying the nlm frame areas into electrical signaling impulses, acathode ray tube having means therein to develop a point source of lightfor illuminatingan area of elemental size on the nlm record, a lighttranslating device arranged to receive light corresponding to thevarying densities of the nlm record as illuminated by the cathode raylight spot .impinging thereon, means for causingthe cathode ray lightspot to traverse the nlm frame areas in a direction transverse to thedirection of nlm motion at a predetermined rate so that each nlm framearea is illuminated with a series of sub- 'stantiallyparallel paths oflight of equal number,

and means for causing the illuminated cathode ray spot to scan adinerent number of equall length transverse paths across the nlm thanthe number of such paths of elemental width which pass the predeterminedpoint within a predetermined time period. k

3. A system for scanning nlm for the television transmission ofelectro-optical reproductions of the independent nlm frame areas whichcomprises means for moving the nlm continuously past a predeterminedpoint at a predetermined. pre-established constant rate correspondingsubstantially to the rate at which the sound recordings on the nlm areto be translated into electrical signaling impulses, a cathode ray tubefor producing a spot of light for illuminating the nlm along a series ofpaths each of elemental width ,transverse to the direction of motion ofthe nlm, and means for causing the cathode ray spot to be displaced'in asecond direction at right angles to that along which the nlm isilluminated so that a different number of nlm frames may be exposed toan identical number of transverse paths of light in a predeterminedtimeperiod than the number of nhn frames which pass the predeterminedpoint in the same time period.

4. The method of producing televisionimages from a motion picture nlmrecord which includes the steps of `moving the nlm record continuouslyat a pre-established constant rate past a prej determined plane ofanalysis, developing an elecy f tron beam within an electron tube andconverting the produced beam into a point source of light ofelementalsize to illuminatean elemental area of proportional sizeon thenlm record, translating the light values on the illuminated elementalnlm areasy into electrical energy of amplitude varying in accordancewith the densitiesy of the elemental areas of the nlm recordilluminated, tracing the developed light spot across the nlm -record ina path transverse to the nlm motion so as to scan the same along a pathtransverse to the path of nlm motion past the predetermined planedenecting the produced electron beam simultaneously in a directionnormal to the plane of the transverse light path traces and controllingthe last named denection in accordance with the nlm motion to return thebeam at predetermined time periods to a plane of initial transversedenection so that a different number of transverse light traces of thenlm are made during a predetermined time period than the actual numberof transverse paths of the same Width which pass the said predeterminedplane of analysis With the nxed predetermined time period.

5. The method of producing-television from a motion picture nlm recordcontinuously which comprises moving the nlm record at a pre-establishedconstant speed past a point of analysis, developing a cathode ray beamto produce a point source of light of elemental area on the nlm, pro-Aducing electrical impulses of variable amplitude proportional to thevarying shade densities on the elemental areas oi the nlm record asilluminated by the cathode ray beam, continuously denecting the cathoderay beam in a plane transverse to the nlm motipn to scan the nlmtransversely in a line for line manner during the nlm motion past thepredetermined point, then denecting the developed beam in a seconddirection normal to the plane of the nrstdenection simultaneously withthe nlm motion, and controlling the cycle of the second named deflectionin accordance with the nlm motion to return the beam to an initial planeof transverse denection at predetermined time intervals for causing theline for line scanning' of the nlm frame areaspassing before thepredetermined point to be of a dinerent number than the lines ofelemental Width of the nlm actually passing the said predetermined pointWithin the said predetermined time period.

6. In television apparatus, a motion picture nlm of which theelectro-optical image reproduction of each nlm frame area yis to beproduced at a distance point, means for moving the nlm at apre-established constant speed past a point of analysis, a cathode raytube having means therein to produce a point source of light ofelemental area, an optical system to direct the light produced withinthe cathode ray tube upon the nlm to illuminate an area of proportionalsize on the nlm, and a light translating device for producing whenilluminated in accordance with the Varying densities of the nlm recordas illuminated by the cathode ray spot varying electrical energy outputcorresponding to the nlmdensity at the elemental area instantaneouslyilluminated, denecting means associated with the cathode ray tube forcausing the cathode ray beam developed to scan the nlm transversely in aline for line manner during the nlm motion past the predetermined pointand a second denecting means for `causing the line for line scanning ofthe nlm frame areas passing before the predetermined y FRITZ SCHRTER.

